Correlation of Chest CT and RT-PCR Testing in Coronavirus Disease 2019 (COVID-19) in China: A Report of 1014 Cases

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ABSTRACT

Background: Chest CT is used for the diagnosis of the 2019 novel coronavirus disease (COVID-19), as an important adjunct to reverse transcription polymerase chain reaction (RT-PCR) tests.
Our purpose was to investigate the diagnostic value and consistency of chest CT compared to RT-PCR assay in COVID-19.

Method: From January 6 to February 6, 2020, 1.014 patients in Wuhan, China, who underwent chest CT and RT-PCR testing, were included. With RT-PCR as the reference standard, the performance of chest CT in the diagnosis of COVID-19 was evaluated. In addition, for patients with multiple RT-PCR assays, we analyzed the dynamic conversion of RT-PCR results (negative to positive, positive to negative, respectively) compared to serial chest CT scans for these patients with time interval of 4 days or more.

Results: Of 1.014 patients, 59% (601/1014) had positive RT-PCR results and 88% (888/1014) had positive chest CT scans. The sensitivity of chest CT suggesting COVID-19 infection was 97% (95% CI, 95-98%, 580/601 patients) based on positive RT-PCR results.
In patients with negative RT-PCR results, 75% (308/413) had positive chest CT findings:

• 308, 48%, were considered as highly probable cases, with 33% as probable cases.

By analyzing serial RT-PCR assays and CT scans:

• The median interval time between initial negative RT-PCR results was 5,1 ± 1,5 days; initial positive to subsequent negative RT-PCR result was 6,9 ± 2,3 days).
• Between 60% and 93% of cases had an initial positive CT scan consistent with COVID-19 before (or in parallel) the initial positive RT-PCR results.
• 42% (24/57) of cases showed improvement on follow-up chest CT scans before RT-PCR results became negative.

Conclusions: Chest CT has a high sensitivity for the diagnosis of COVID-19. Chest CT can be considered as a main tool for the current detection of COVID-19 in epidemic areas.